1. Field of the Invention
The present invention relates to a tool for sizing an O.D. surface of a cylindrical workpiece by means of a size-adjustable cylindrical bore having abrasive particles for sizing the workpiece.
2. Background Art
There is considerable prior art relating to the honing, deburring, lapping, finishing, and superfinishing of bores by means of various tooling structures. However, there is no known prior art which addresses problems associated with the accurate sizing of an outside diameter (O.D.) surface of a cylindrical workpiece for close tolerancing. For example, a pulley hub for a timing belt may require close tolerancing on its O.D. surface, and may require accurate concentricity of the O.D. surface with respect to the central axis of the hub. This close tolerancing may not be achieved with existing prior art turning or lathing operations.
Accordingly, there remains a need in the art for inexpensive machine tools for sizing O.D. surfaces of cylindrical workpieces in a manner in which precise size tolerancing can be achieved and concentricity with respect to a central axis of the workpiece can be achieved.
The present invention overcomes the above-referenced shortcomings of prior art O.D. surface sizing operations by providing a tool for sizing the O.D. surface of a cylindrical workpiece which includes an adjustable interior bore having abrasive particles thereon for accurately sizing the cylindrical workpiece.
As used herein, the term xe2x80x9csizingxe2x80x9d is used to refer to finishing, superfinishing, lapping, deburring, polishing, or machining.
Preferably, the tool comprises a rotatable substantially cylindrical member (or xe2x80x9ccylindrical portionxe2x80x9d) having an inner work-engaging surface adapted for finishing the O.D. surface of the cylindrical workpiece. The inner work-engaging surface includes abrasive particles thereon and defines a bore to receive the workpiece. The substantially cylindrical member includes at least one longitudinal split permitting radial expansion and contraction of at least part of the cylindrical portion for workpiece O.D. size adjustment.
An adjustment nut is threaded onto the substantially cylindrical member. The adjustment nut and substantially cylindrical member include at least one tapered adjustment surface therebetween which is operative as a cam to facilitate the expansion and contraction as the adjustment nut is rotated with respect to the substantially cylindrical member.
In one embodiment, the tapered adjustment surface is formed on an outside surface of the substantially cylindrical member. The adjustment nut includes at least one rubber preload ring engaged with the tapered adjustment surface to provide an adjustable compressive force on the substantially cylindrical member as the adjustment nut is rotated with respect to the substantially cylindrical member. This embodiment is particularly used for superfinishing the O.D. surface.
In another embodiment, the substantially cylindrical member comprises a tapered outer surface and the adjustment nut comprises a tapered portion slidably engageable with the tapered outer surface as the nut is rotated with respect to the substantially cylindrical member to provide an adjustable compressive force on the substantially cylindrical member as a result of interference-type engagement between the tapered portion of the nut and the tapered outer surface of the substantially cylindrical member. This structure is more rigid than the above-described embodiment, and is used primarily for rough-cutting, as opposed to superfinishing.
Accordingly, an object of the invention is to provide a tool for accurately sizing an O.D. surface of a cylindrical workpiece.
Another object of the invention is to provide a tool for accurately sizing an O.D. surface of a cylindrical workpiece which includes a cylindrical member defining a bore bordered by abrasive particles to receive and size the workpiece.
The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.